/*
 * Copyright 2002-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.http.client;

import java.io.Closeable;
import java.io.IOException;
import java.net.URI;

import org.apache.http.client.HttpClient;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.methods.Configurable;
import org.apache.http.client.methods.HttpUriRequest;
import org.apache.http.client.protocol.HttpClientContext;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.nio.client.CloseableHttpAsyncClient;
import org.apache.http.impl.nio.client.HttpAsyncClients;
import org.apache.http.nio.client.HttpAsyncClient;
import org.apache.http.protocol.HttpContext;

import org.springframework.beans.factory.InitializingBean;
import org.springframework.http.HttpMethod;
import org.springframework.util.Assert;

/**
 * Asynchronous extension of the {@link HttpComponentsClientHttpRequestFactory}. Uses
 * <a href="http://hc.apache.org/httpcomponents-asyncclient-dev/">Apache HttpComponents
 * HttpAsyncClient 4.0</a> to create requests.
 *
 * @author Arjen Poutsma
 * @author Stephane Nicoll
 * @see HttpAsyncClient
 * @since 4.0
 * @deprecated as of Spring 5.0, with no direct replacement
 */
@Deprecated
public class HttpComponentsAsyncClientHttpRequestFactory extends HttpComponentsClientHttpRequestFactory
        implements AsyncClientHttpRequestFactory, InitializingBean {

    private HttpAsyncClient asyncClient;


    /**
     * Create a new instance of the {@code HttpComponentsAsyncClientHttpRequestFactory}
     * with a default {@link HttpAsyncClient} and {@link HttpClient}.
     */
    public HttpComponentsAsyncClientHttpRequestFactory() {
        super();
        this.asyncClient = HttpAsyncClients.createSystem();
    }

    /**
     * Create a new instance of the {@code HttpComponentsAsyncClientHttpRequestFactory}
     * with the given {@link HttpAsyncClient} instance and a default {@link HttpClient}.
     *
     * @param asyncClient the HttpAsyncClient instance to use for this request factory
     * @since 4.3.10
     */
    public HttpComponentsAsyncClientHttpRequestFactory(HttpAsyncClient asyncClient) {
        super();
        this.asyncClient = asyncClient;
    }

    /**
     * Create a new instance of the {@code HttpComponentsAsyncClientHttpRequestFactory}
     * with the given {@link CloseableHttpAsyncClient} instance and a default {@link HttpClient}.
     *
     * @param asyncClient the CloseableHttpAsyncClient instance to use for this request factory
     */
    public HttpComponentsAsyncClientHttpRequestFactory(CloseableHttpAsyncClient asyncClient) {
        super();
        this.asyncClient = asyncClient;
    }

    /**
     * Create a new instance of the {@code HttpComponentsAsyncClientHttpRequestFactory}
     * with the given {@link HttpClient} and {@link HttpAsyncClient} instances.
     *
     * @param httpClient  the HttpClient instance to use for this request factory
     * @param asyncClient the HttpAsyncClient instance to use for this request factory
     * @since 4.3.10
     */
    public HttpComponentsAsyncClientHttpRequestFactory(HttpClient httpClient, HttpAsyncClient asyncClient) {
        super(httpClient);
        this.asyncClient = asyncClient;
    }

    /**
     * Create a new instance of the {@code HttpComponentsAsyncClientHttpRequestFactory}
     * with the given {@link CloseableHttpClient} and {@link CloseableHttpAsyncClient} instances.
     *
     * @param httpClient  the CloseableHttpClient instance to use for this request factory
     * @param asyncClient the CloseableHttpAsyncClient instance to use for this request factory
     */
    public HttpComponentsAsyncClientHttpRequestFactory(
            CloseableHttpClient httpClient, CloseableHttpAsyncClient asyncClient) {

        super(httpClient);
        this.asyncClient = asyncClient;
    }


    /**
     * Set the {@code HttpAsyncClient} used for
     * {@linkplain #createAsyncRequest(URI, HttpMethod) synchronous execution}.
     *
     * @see #setHttpClient(HttpClient)
     * @since 4.3.10
     */
    public void setAsyncClient(HttpAsyncClient asyncClient) {
        Assert.notNull(asyncClient, "HttpAsyncClient must not be null");
        this.asyncClient = asyncClient;
    }

    /**
     * Return the {@code HttpAsyncClient} used for
     * {@linkplain #createAsyncRequest(URI, HttpMethod) synchronous execution}.
     *
     * @see #getHttpClient()
     * @since 4.3.10
     */
    public HttpAsyncClient getAsyncClient() {
        return this.asyncClient;
    }

    /**
     * Set the {@code CloseableHttpAsyncClient} used for
     * {@linkplain #createAsyncRequest(URI, HttpMethod) asynchronous execution}.
     *
     * @deprecated as of 4.3.10, in favor of {@link #setAsyncClient(HttpAsyncClient)}
     */
    @Deprecated
    public void setHttpAsyncClient(CloseableHttpAsyncClient asyncClient) {
        this.asyncClient = asyncClient;
    }

    /**
     * Return the {@code CloseableHttpAsyncClient} used for
     * {@linkplain #createAsyncRequest(URI, HttpMethod) asynchronous execution}.
     *
     * @deprecated as of 4.3.10, in favor of {@link #getAsyncClient()}
     */
    @Deprecated
    public CloseableHttpAsyncClient getHttpAsyncClient() {
        Assert.state(this.asyncClient instanceof CloseableHttpAsyncClient,
                "No CloseableHttpAsyncClient - use getAsyncClient() instead");
        return (CloseableHttpAsyncClient) this.asyncClient;
    }


    @Override
    public void afterPropertiesSet() {
        startAsyncClient();
    }

    private HttpAsyncClient startAsyncClient() {
        HttpAsyncClient client = getAsyncClient();
        if (client instanceof CloseableHttpAsyncClient) {
            CloseableHttpAsyncClient closeableAsyncClient = (CloseableHttpAsyncClient) client;
            if (!closeableAsyncClient.isRunning()) {
                closeableAsyncClient.start();
            }
        }
        return client;
    }

    @Override
    public AsyncClientHttpRequest createAsyncRequest(URI uri, HttpMethod httpMethod) throws IOException {
        HttpAsyncClient client = startAsyncClient();

        HttpUriRequest httpRequest = createHttpUriRequest(httpMethod, uri);
        postProcessHttpRequest(httpRequest);
        HttpContext context = createHttpContext(httpMethod, uri);
        if (context == null) {
            context = HttpClientContext.create();
        }

        // Request configuration not set in the context
        if (context.getAttribute(HttpClientContext.REQUEST_CONFIG) == null) {
            // Use request configuration given by the user, when available
            RequestConfig config = null;
            if (httpRequest instanceof Configurable) {
                config = ((Configurable) httpRequest).getConfig();
            }
            if (config == null) {
                config = createRequestConfig(client);
            }
            if (config != null) {
                context.setAttribute(HttpClientContext.REQUEST_CONFIG, config);
            }
        }

        return new HttpComponentsAsyncClientHttpRequest(client, httpRequest, context);
    }

    @Override
    public void destroy() throws Exception {
        try {
            super.destroy();
        } finally {
            HttpAsyncClient asyncClient = getAsyncClient();
            if (asyncClient instanceof Closeable) {
                ((Closeable) asyncClient).close();
            }
        }
    }

}
